The present invention relates, in general, to an injection assembly for an injection molding machine.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
U.S. Pat. No. 5,540,495 describes an injection assembly having injection and rotary drives which are arranged in coaxial relationship to a plasticizing screw and which are each constructed in the form of a hollow-shaft drive. The injection and rotary drives are securely fixed to a housing and the plasticizing barrel which accommodates the plasticizing screw. During turning as well as movement in injection direction, the plasticizing screw is securely fixed to the threaded shaft of the screw mechanism which implements the injection stroke of the injection drive, and connected in fixed but axially movable engagement with a drive element of the rotary drive. As a result, the screw mechanism is subject to substantial axial as well as radial stress and thus exposed to increased risk of wear, even when constructed as ball screw mechanism.
It would therefore be desirable and advantageous to provide an improved injection assembly to obviate prior art shortcomings.